Pass detailed error message along to user if possible (closes #7)

[crew102]

This PR attempts to parse the error message contained in the body of the API's response. If the message can be parsed, it's passed along to the user in a detailed error message. Otherwise, a generic error message corresponding to the HTTP status code is provided. Closes #7.

Examples

This is what error messages look like in the current version of microdemic (note, I have fauxpas installed, so raise_for_status() is calling fauxpas::http() for error handling - https://github.com/ropensci/crul/blob/dba96adc1685aa237b9465074adcf2e00f675ac5/R/response.R#L149-L154).

library(microdemic)

ma_evaluate(
  query = "bad-query",
  key = Sys.getenv("MICROSOFT_ACADEMIC_KEY"),
)
#> Error: Bad Request (HTTP 400)

ma_evaluate(
  query = "Y=[2010, 2012)",
  key = Sys.getenv("MICROSOFT_ACADEMIC_KEY"),
  offset = "bad-offset"
)
#> Error: Bad Request (HTTP 400)

ma_evaluate(
  query = "Y=[2010, 2012)",
  key = "bad_key"
)
#> Error: Unauthorized (HTTP 401)

Examples of error messages when using version of microdemic found in this PR:

library(microdemic)

# The detailed error message provided by the API is literally "Invalid query 
# expression\r\nParameter name: expression"
ma_evaluate(
  query = "bad-query",
  key = Sys.getenv("MICROSOFT_ACADEMIC_KEY"),
)
#> Error: 400 (HTTP Bad Argument)
#> Explanation: Invalid query expression
#> Parameter name: expression

ma_evaluate(
  query = "Y=[2010, 2012)",
  key = Sys.getenv("MICROSOFT_ACADEMIC_KEY"),
  offset = "bad-offset"
)
#> Error: 400 (HTTP Bad Argument)
#> Explanation: offset should be an integer

ma_evaluate(
  query = "Y=[2010, 2012)",
  key = "bad_key"
)
#> Error: 401 (HTTP Unspecified)
#> Explanation: Access denied due to invalid subscription key. Make sure you are subscribed to an API you are trying to call and provide the right key.

Examples of error messages if parsing of error message fails in parse_error_msg(). This is also what error messages look like in the current version of microdemic if the user doesn't have fauxpas installed.

library(microdemic)

ma_evaluate(
  query = "bad-query",
  key = Sys.getenv("MICROSOFT_ACADEMIC_KEY"),
)
#> Error: 400 (HTTP Bad Request)
#> Explanation: Bad request syntax or unsupported method

ma_evaluate(
  query = "Y=[2010, 2012)",
  key = Sys.getenv("MICROSOFT_ACADEMIC_KEY"),
  offset = "bad-offset"
)
#> Error: 400 (HTTP Bad Request
#> Explanation: Bad request syntax or unsupported method

ma_evaluate(
  query = "Y=[2010, 2012)",
  key = "bad_key"
)
#> Error: 401 (HTTP Unauthorized)
#> Explanation: No permission -- see authorization schemes

[codecov-io]

Codecov Report

Merging #12 into master will increase coverage by 4.32%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #12      +/-   ##
==========================================
+ Coverage   73.56%   77.88%   +4.32%     
==========================================
  Files           8        8              
  Lines          87      104      +17     
==========================================
+ Hits           64       81      +17     
  Misses         23       23

Impacted Files	Coverage Δ
R/zzz.R	89.58% <100%> (+5.71%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 39ea083...d9121ea. Read the comment docs.

[sckott]

thanks, having a look

[sckott]

LGTM, thanks very much

[sckott]

@crew102 want to be an author?

[crew102]

Sure, that would be nice, thanks. How about I start off as a contributor and if I work more on the package in the future than we can bump to author?